We have experimented with these 4 methods of converting lawn to wildflowers. Since there is lot of interest in this currently, I wanted to share what we have learned so far. Each pic will have a description of what went into making it. Hope this inspires you! The birds, bugs, bees, and yourself will be glad you did it.
Overall notes-
1. Winter seeding is best. Some seeds need the cold and damp of winter to trigger germination in spring. This is called stratification and is especially important for many native plants. A seed blend spread in summer did not produce the same plants as the exact same blend spread in summer.
2. Tilling may have the unintended effect of bringing more “bad” seeds to the soil surface where they’ll germinate and compete with your seed blend. A no-till option would be to just cut the grass low right before smothering.
3. Seed blends will evolve. Some annual flowers will go crazy the first year. They may or may not re-seed themselves into the future. Blends will likely have perennial flowers that will slowly build strength and take over in following years.
4. Tarps can be standard woven tarps or really anything impervious. Can be clear plastic, and that may even be better because it cooks the turf with the greenhouse effect (but clear plastic is weaker and harder to hold down.)
5. Maintenance will be required for establishing. Weeding and sometimes watering, depending on how rainy the season is. Download a good plant ID app to help. I use “Picture This” which is free at first, then $20 a year, but there are many other options.
6. All these seeded patches are blends which are not specifically natives, but contain some natives. This type of blend is much easier to establish than purely natives, which are slow and somewhat fussy.
Method 1- Tarp and Till. Pro: “set it and forget it” Con: Tarps on the lawn are kinda ugly.
Process- Tarps were spread on high grass in mid-summer 2020, tilled the dead grass into the ground in November 2020, and spread seed in January 2021. Seeded ground was trampled to get good seed-soil contact.
Reasoning- Mid summer heat is the best time to start killing lawn. Tilled in November before the ground froze. We let the tall grass become more organic matter in the soil by lightly tilling it in.
Results- Lots of beautiful poppies the first year that did not appear in the “method 2” bed at all because they did not get the overwinter stratification (see notes.) This has evolved into many native perennials like the coreopsis and coneflower here.
Method 2- Just till. Pro: Ready to seed quickly. Cons: Effort of weeding and watering.
Process- Low mowed and deep tilled a small area in June 2020. Some compost was added to
boost soil fertility. Seed spread and trampled immediately after. Patch had to be weeded regularly, especially from grass, until the seeds started taking off. Watering requiring since we missed the spring moisture.
Reasoning- This was the original test patch. We got a late start so tilling was necessary since we had not smothered the previous year.
Results- Tons of Mexican Sunflower (Tithonia) the first year, a real hummingbird magnet… that wasn’t even supposed to be in seed blend! Too much Evening Primrose the second year, so we removed a lot of it to make room for other stuff. Lots of amaranth that grows comically long, purple cascading flowers. This has become the catch-all bed where I plant any extra perennials.
Method 3- Organics, cardboard, and mulch. Pro: Builds soil. Con: Higher effort.
Process- Turf was covered with leaves and grass clippings, then cardboard and mulch in May 2020. This was left as-is until May 2021. We then planted purchased native plants through the cardboard.
Reasoning- We left this for a year for the leaves and grass clippings to decompose and make better soil. This method is specifically for planting plants or “plugs” since you cannot seed on mulch. Plants that grow by spreading were selected, rather than seed spreaders. We wanted to showcase native plants, and have them organized for maximum bloom time and height (low to high, front to back.)
Results- Natives are slow to establish, but buying plants meant they were older than seedlings and many bloomed the first year. We were able to collect seed and use them in future plantings. The species of insects that these natives draw in is amazing to see. This bed will require weeding and re-mulching for a few years until the plants spread and fill in the spaces more. Doesn’t look like much now, but will soon when those 6 foot tall Blazing Stars pop off.
Method 4- Spray and seed. Pro: low effort. Con: herbicide.
Process- This area of lawn was ALL dandelion (which we have plenty of elsewhere) and those were sprayed in late summer 2021. The bare earth was raked smooth, then seeded with a cheap wildflower blend in May 2022. This was watered regularly between rains until it took off.
Reasoning- Because I had bare ground and wanted to see how low-effort I could go with a wildflower patch!
Results- Decent growth so far in a very young bed. It will need weeded the first couple years but will hopefully fill in with perennial plants over time. Not bad for $12 of seed and an hour of work.
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